Patient registries are often
integrated into routine clinical practice with systematic and sometimes
automated data capture in electronic healthcare records, but disease, exposure
or outcome-specific registries usually require recording of specific relevant
data. Whilst the duration of a registry is normally open-ended, that of a study
is dictated by the time needed to define and collect data relevant for the
specific study objectives. Studies also often require introduction of specific
procedures, questionnaires or data collection tools. Studies are set up and
managed based on limited endpoints and a specific protocol, whereas patient
registries are traditionally set up focusing on system(s) specifications in
order to ensure a continuous, efficient and collaborative data collection; safe
data hosting; accessible, retrievable, interoperable and re-usable data.

A registry can be used as a
source of patients for studies based on either primary data collection (where
the data collected for new patients are also used for a specific study) or
secondary data collection (analogously to the use of electronic healthcare
records). For this purpose, registries data can be enriched with additional
information on outcomes, lifestyle data, immunisation and mortality information
obtained from linkage to the existing database such as national cancer
registries, prescription databases or mortality records.